Recycled Cathode Active Material via Thermal Impurity Removal
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Solution Overview
Problem
Existing methods for recycling cathode active materials from lithium secondary batteries result in environmental pollution, high costs, and degraded battery characteristics due to incomplete removal of impurities and the use of toxic solvents or acids, with risks of explosion and excessive energy consumption.
Innovation Solution
A method involving thermal decomposition and reheat treatment of waste cathodes to remove conductive materials and binders, followed by annealing with a lithium precursor and optional surface coating, without pre-washing, to achieve complete impurity removal and reduced internal and external resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If acid dissolution method is used to recover rare metals from waste cathode, then rare metals can be extracted, but neutralization and wastewater treatment processes are required which greatly increases process costs and causes environmental pollution
Solution Approach 1:
The patent extracts and removes the harmful acid dissolution step from the recycling process. Instead of using acid to dissolve the cathode and then extracting rare metals, the invention directly recovers the cathode active material through thermal treatment, effectively taking out the problematic chemical extraction stage while still achieving rare metal recovery.
Solution Approach 2:
The patent converts the harmful acid dissolution process into a beneficial thermal treatment process. By using heat treatment at controlled temperatures, the binder and conductive materials are decomposed and removed, while the cathode active material containing rare metals is preserved and recovered in high purity, transforming a harmful chemical process into a beneficial physical-chemical process.
2Manufacturing precision
If pre-washing process is used to remove impurities from recovered cathode active material, then impurity removal is achieved, but the process becomes complex and productivity decreases
Solution Approach 1:
The patent performs preliminary impurity removal through controlled thermal treatment before recovery. By heating the waste cathode at 300-650°C, the binder and conductive materials are decomposed and volatilized in advance, so that when the cathode active material is recovered, impurities are already removed, eliminating the need for subsequent pre-washing operations.
Solution Approach 2:
The patent replaces the mechanical/chemical washing system with a thermal treatment system. Instead of using water or chemical solutions to wash and remove impurities, the invention uses controlled heating to decompose and volatilize organic impurities (binder and conductive materials), substituting a simpler thermal process for complex washing operations.
3Manufacturing precision
If solvent dissolution method is used to dissolve binder, then binder removal is achieved, but toxic gases are generated and explosion hazards occur requiring expensive solvent recovery process
Solution Approach 1:
The patent converts the harmful solvent dissolution process into a beneficial thermal decomposition process. By heating the waste cathode at 300-650°C, the binder and conductive materials undergo controlled thermal decomposition, converting toxic organic solvents into harmless gaseous products (CO2, H2O) that can be safely vented, while still achieving complete binder removal.
Solution Approach 2:
The patent changes the fundamental parameter of binder removal from chemical dissolution (using solvents) to thermal decomposition (using heat). By controlling the temperature parameter within 300-650°C, the binder and conductive materials are decomposed into volatile products, achieving effective removal without the harmful effects of organic solvent usage.
4Ease of manufacture
If aluminum foil dissolution method is used to remove current collector, then binder removal is easy and process cost is low, but foreign substances are formed on surface and hydrogen gas explosion risk occurs
Solution Approach 1:
The patent changes the temperature parameter and chemical environment to avoid aluminum foil dissolution reactions. By controlling the thermal treatment temperature and using an oxidizing atmosphere, the binder is decomposed without reacting with the aluminum current collector, preventing hydrogen gas formation and surface contamination while maintaining process simplicity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method reduces wastewater generation, eliminates the need for acid use, prevents toxic gas formation, and enhances the efficiency, lifespan, and resistance characteristics of the recycled cathode active material, improving economic and productivity outcomes.
Implementation Method 1
thermally decomposing a binder and a conductive material in a cathode active material layer by heat-treating, at 300 to 650 °C, a waste cathode
Implementation Method 2
reheating the recovered cathode active material at 350 to 700 °C for 1 to 10 hours... impurities derived from a conductive material or binder remaining on the surface of the recovered cathode active material may be completely removed
Implementation Method 3
adding a lithium precursor to the reheat-treated cathode active material and performing annealing at 500 to 1000 °C
Data Source
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AI summary
The present invention relates to a method of recycling a cathode active material and a recycled cathode active material prepared using the same. More particularly, the present invention relates to a method of recycling a cathode active material, the method including step (a) of thermally decomposing a binder and a conductive material in a cathode active material layer by heat-treating, at 300 to 650 °C, a waste cathode having the cathode active material layer formed on a current collector to separate the current collector from the cathode active material layer and recover a cathode active material in the cathode active material layer; step (b) of reheating the recovered cathode active material at 350 to 700 °C for 1 to 10 hours; step (c) of adding a lithium precursor to the reheat-treated cathode active material and performing annealing at 500 to 1000 °C; step (d) of washing the annealed cathode active material with a washing solution; and step (e) of surfacecoating the washed cathode active material with a coating agent, and a cathode active material prepared using the same.